Sprechen kann die Reaktion auf Augenbewegungen verlangsamen und möglicherweise die Sicherheit des Fahrers gefährden, indem es die zur Gefahrenerkennung erforderlichen visuellen Beurteilungen verzögert und körperliche Reaktionen verlangsamt

> New study shows that everyday conversations can delay eye movements, essential for safe driving

>To investigate this, the researchers asked 30 healthy adults to perform rapid center-out eye-movement tasks under three different conditions: talking, listening, and a no-task control. Participants were instructed to look as quickly and accurately as possible toward a peripheral visual target presented in one of eight directions. In the talking condition, participants answered general knowledge and episodic questions adapted from the Wechsler Adult Intelligence Scale and additional custom prompts. In the listening condition, participants listened to passages from the Japanese novel I Am a Cat. The order of conditions was randomized across three separate days. Across all participants, talking produced clear and consistent delays in three key temporal components of gaze behavior: the time needed to initiate the eye movement after target appearance (reaction time), the time needed to reach the target (movement time), and the time needed to stabilize gaze on the target (adjusting time). None of these effects were observed during listening or control conditions, suggesting that the act of talking and the cognitive effort required to search for and produce verbal answers create meaningful interference with gaze control mechanisms.
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>These delays appear small in isolation, but during driving, they may accumulate into slower detection of hazards and delayed initiation of physical responses. Even hands-free conversations may introduce a cognitive load strong enough to interfere with the neural processes that initiate and guide eye movements. Because drivers often need to look downward toward pedestrians, debris, or objects on the road, these delays highlight the broad risks of conversation during visually demanding driving scenarios

[Talking-associated cognitive loads degrade the quality of gaze behavior | PLOS One](https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0333586)

I wonder if there is any impact on the other person involved in the conversation. Anecdotally, I think it takes much more brain power to talk to a random person compared to my SO.